Many industrial processes involve liquid deposition, then heating, followed by a liquid cleaning procedure to remove residue. For example, in a flip chip attachment process, solder flux may be applied by jetting, pin transferring, or printing the solder flux on a substrate prior to placing the flip chip on the substrate. In many cases, the solder flux must have a relatively high viscosity in order to hold the flip chip in place before a solder joint is formed. Such a solder joint may be formed in a reflow process (i.e., heating a flip chip assembly in a reflow oven). After the reflow process, corrosive solder flux residue may remain. Such solder flux residue may be removed by water or some other cleaning agent to prevent corrosion. However, as a result of heating in the reflow process, the solder flux residue typically has a viscosity that is much higher than that of the original solder flux due to evaporation of volatile components, which typically have lower viscosities. This may make removing the solder flux residue more difficult, particularly when trying to access low clearance spaces (e.g., underneath the flip chip) with water or some other cleaning agent.
Another example of a soldering process is car radiator manufacturing and repairing. In such a process, viscous solder flux is typically applied to a copper tube and a fitting cup to facilitate the soldering process. During the soldering process, the solder flux is heated and a solder flux residue may remain. After the soldering process, the solder flux residue may be removed by water or some other cleaning agent to prevent corrosion. However, as discussed above, the solder flux residue typically has a higher viscosity than that of the original solder flux, which may make removing the solder flux residue more difficult.
Removing solder flux residue has never been a particularly easy task. And it is getting more difficult as a result of a ban on chlorofluorocarbons (CFC's) and other halide chemicals as cleaning solvents. Attempts to lessen the difficulty of removing solder flux residue have largely focused on the use of special defluxing agents and special cleaning instruments and processes. However, all of these attempts have drawbacks. For example, many defluxing agents are flammable and thus may create a fire hazard. Also, special cleaning instruments can be expensive to design, manufacture, and maintain. Further, special cleaning processes often include multiple time-consuming, and thus costly, steps.
In view of the foregoing, it may be understood that there are significant problems and shortcomings associated with current techniques for cleaning or otherwise removing solder flux residue from various surfaces after a heating process.